Ground effect vehicles



Oct. 4, 1966 c. H. LATlMER-NEEDHAM 3,276,529

GROUND EFFECT VEHI CLES 4 Sheets-Sheet 1 Filed June 11, 1964 BY seqATTORNEYS Oct. 4, 1966 c. H. LATlMER-NEEDHAM 3,276,529

GROUND EFFECT VEHICLES Filed June 11, 1964 4 Sheets-Sheet 2 BY g twi cyDa /91 ATTORNEYS Oct. 4, 1966 c. H. LATlMER-NEEDHAM 3,276,529

GROUND EFFECT VEHICLES Filed June 11, 1964 4 Sheets-Sheet 5 ATTORNEYSUnited States Patent 3,276,529 GROUND EFFECT VEHICLES Cecil HughLatimer-Needham, Wonersh, near Guildford,

England, assignor to Westland Aircraft Limited, Somerset, England FiledJune 11, 1964, Ser. No. 374,394 Claims priority, application GreatBritain, June 18, 1963, 24,135/ 63 8 Claims. (Cl. 180--7) This inventionrelates to improvements in machines or vehicles of the type which employa pressurized gas cushion or cushions to wholly or partially support thevehicle above the surface over which it is hovering or moving. Variousforms of such vehicles have been proposed in which a cushion ofpressurized gas is maintained between the ground, water or other surfaceand the underside of the vehicle to wholly or partially support thevehicle, and these machines are generally known in the art as groundeffect machines.

For obvious practical reasons in the operation of such machines, it isdesirable in most cases to maintain the pressurized gas supportingcushion of such a depth as to have the main structure of the vehicleride at a practical clearance above the surface over which the vehicleis operating. One of the more substantial problems encountered in thedesign and operation of these vehicles relates to the retention of thepressurized gas cushion or cushions beneath the vehicle, which problemis increased or multiplied as the depth of the supporting cushionincreases. This invention is directed toward an arrangement for reducingor minimizing this loss of pressurized gas from the supporting cushion.It has already been proposed in ground effect machines to employ themomentum of a fluid to retain the pressurized cushion of air, the fluidbeing utilized in the form of a fluid curtain around part or all of thepressurized supporting cushion. While this arrangement presents severaladvantages and desirable features, it is subject to the disadvantages ofrequiring a relatively large amount of power to pressurize the curtainfluid and a relatively large amount of space for containing therequisite ducting. Also, to increase the ground clearance of groundeflect machines while minimizing loss of cushion air, various forms offlexible skirt members have been utilized to depend from the basestructure of the machine and form flexible physical barriers around partor all of the pressurized supporting cushion. Finally, to retain thepressurized cushion of air beneath water based ground efiect machines,the machines have been provided with side walls which depend from themain structure and create a longitudinal physical seal between theunderside of the vehicle and the water. One such embodiment of sidewalls is disclosed in British Patent No. 935,531. However, such sidewall machines have generally been limited to operation overwater, :andhave been subject to the added disadvantage of substantial losses ofcushion air at points around the base structure of the machine which arenot sealed by the longitudinal side walls.

In ground effect machines having either rigid or flexible skirtsdepending from the base structure, difliculties are often encounteredbecause of obstructions which project above the general surface overwhich the vehicle is traveling. While properly constructed flexibleskirts tend in many instances to fold or give way and pass over theobstruction, in some instances there is a tendency for the skirt to betorn or damaged or to become temporarily hooked in some projectingobstruction. In cases where the skirt is rigid or where the main basestructure rides relatively close to the surface, these abruptobstructions or projections prevent even more substantial difliculties,especially where a rigid skirt may extend transversely across the widthof the machine. While the side wall members of a side wall type machinedo not extend transversely across the width of the Vehicle, and thusminimize this problem to some extent, this is accomplished at theexpense of pressure tightness of the supporting air cushion.

While this invention relates generally to ground effect machines and toarrangements for minimizing air losses from the pressurized supportingcushion without increasing the difliculties created by encounteredobstacles or obstructions, it relates more particularly to a machine ofthe side wall type wherein air losses from the pressurized supportingcushion are reduced or minimized without attendant difficulties due toabrupt projections or obstructions in the path of the vehicle, andwithout the common difliculties which often accompany the use offlexible skirts.

Accordingly, it is an object of this invention to provide such -amachine embodying features minimizing retardation of movement and/0rdamage to the machine due to obstacles in the path of the vehicle.

It is a further object of this invention to provide apparatus whichminimizes the leakage of air from the pressurized gas supporting cushionbetween the ground, water or other surface over which the vehicle isoperating and the base structure of the vehicle.

It is a further object of this invention to provide a ground effectmachine capable of eflicient and economical operation over both land andwater.

With the foregoing objects in mind, the invention comprises a groundeffect machine comprising a load carrying platform provided with atleast two depending side walls between which the longitudinal centerline of the vehicle passes, one or more transversely disposed rollersextending between the depending side walls, whereby the side walls andthe roller or rollers define boundary sides of a pressurized gassupporting cushion under the base structure. Preferably two or more suchrollers are provided so as to completely enclose the pressurized gascushion area, the rollers themselves preferably being formed from aflexible material and being inflated to a relatively low pressure. Therollers are preferably pivotally mounted so as to give way in the faceof encountered obstacles, and means are provided to urge the rollersback to their extended position after the obstacle has been cleared. Inorder to minimize cushion air losses between the upper surface of theroller and the base structure of the vehicle pressurized cushion airpreferably is supplied to the supporting cushion in the form of a fluidcurtain extending transversely across the base structure of the vehiclebetween the transverse center line of the base structure and theclearance space between the roller and the base structure. The elongatednozzle for producing this fluid curtain can be extended below the basestructure of the vehicle in the form of a hollow flexible member havingan elongated nozzle along its lower edge. Appropriate sealingarrangements are provided to the most practical extent between the endsof the roller or rollers and the inner surfaces of the depending sidewalls, these sealing arrangements being flexible or yieldable so as topermit pivotal movement of the rollers and vertical extension orretraction of the side Walls.

Referring now to the accompanying drawings for a more detaileddescription of an exemplary embodiment or exemplary features of theinvention.

FIG. 1 is a side view with parts broken away of a side wall machineemploying fore and aft transverse rollers according to the invention,

FIG. 2 is a front view of the machine shown in FIG. 1,

FIG. 3 is a sectional view showing the details of an exemplary rollerconstructed according to the invention,

FIG. 4 illustrates the manner in which the nozzle for supplying thepressurized supporting air may be flexibly extended downwardly toenhance the effectiveness of the sealing arrangement,

FIG. 5 is a view partly in section of the front part of an exemplarymachine showing the manner in which the inflated roller may be mountedto the base structure so as yieldably to pivot upon encountering anobstacle,

FIG. 6 is an illustration of an exemplary arrangement for retracting andextending the side walls of the machine,

FIGS. 7 and 8 are respectively a front view and a plan sectional viewillustrating an exemplary sealing arrangement between the rollersupporting arms and the side walls of the machine,

FIG. 9 illustrates an embodiment of the invention utilizing a smallerroller in conjunction with a flexible skirtlike member for supportingthe roller.

Referring first to FIGS. 1 and 2, the main load carrying platformstructure or base structure of the machine is generally labeled 1, andhas longitudinally extending side wall members 2 and 3 depending fromthe outer edges thereof. Transverse rollers 4 and 5 are pivotallymounted to the base structure by arms 11 and 13, and these arms areresiliently urged to the extended positions shown in FIG. 1 by hydraulicor spring operated members 12 and 14. Members 12 and 14 can take theform of shock absorbers of known types, utilizing either springs orhydraulic pressure or a combination of these to yieldably urge theroller supporting arms to their normal positions. Rollers 4 and 5 aremounted upon axles 15 which in turn are journaled in the lower ends ofarms 11 and 13. The two rollers combine with the depending side walls todefine an open-bottomed box into which pressurized air is ducted to formthe supporting cushion for the vehicle. Air for the supporting cushionis drawn into intake duct 8 by blower 7, which is driven from enginescarried in the base structure of the vehicle in a manner well known inthe art. Preferably the pressurized air from blower 7 is forced into thesupporting cushion area through elongated nozzle openings 9 and whichopen downwardly across the base structure of the vehicle between theinner surfaces of the depending side Walls. The pressurized air issuesfrom these nozzle openings in the form of a fluid curtain, and thenozzle openings are arranged so as to lie transversely of the basestructure adjacent to but inwardly of the clearance space between theupper surfaces of the rollers and the lower surface of the basestructure. Thus these fluid curtains tend to reduce or minimize thepossible loss of cushion air through these clearance spaces.

The air rollers preferably are in the form of inflatable cylinders madeof impermeable flexible material, such as rubberized or impregnatedfabric. As shown in FIG. 3, the cylinders are closed at both ends, andpreferably an inner sleeve of the same or a similar material extendsbetween the ends of the main cylinder so as to prevent or minimizepossible bulging longitudinally outwardly of the end material of themain roller. Inner cylinder 17 may be replaced if desired by individualties which would similarly avoid undue curvature of the end material, oralternatively the ends of the main roller could be formed from .arelatively stiffer flexible material which in itself would avoid unduecurvature. Inner radial diaphragm members 16 are provided at spacedpoints along the main cylinder to brace the outer wall of the maincylinder against undue bulging or outward curvature, thus maintainingthe outer surface of the main cylinder in a straight line to the extentthat this is possible. Diaphragm members 16 may be incorporated in anydesired number, and preferably are formed from substantially the samematerial as the main roller. Axle preferably passes completely throughthe main roller and is clamped to the end portions of the main roller byclamping members 18, which can take the form of spaced discs havingmeans for clamping the flexible end material therebetween. In thosecases where the entire inner space of the main roller is pressurized,clamping members 18 should be sealed to shaft 15 in any of severalpressure tight manners which are well known in the art. When innercylinder 17 is formed of an impermeable material, then appropriateopenings should be provided therein so as to permit the entire spaceinside main cylinder 4 to be pres surized.

The air rollers may be inflated by any suitable means, the particularinflation arrangement forming no part of the instant invention. Forinstance, an air passage may be provided through the interior of theaxle 15 to the space inside the cylinder 4. In those instances where itmay be desired to provide for varying the pressure inside the rollerduring operation of the vehicle, an appropriate gland joint could beprovided in the arms 11 where the axle 15 is journaled. Alternatively,the axle 15 could be journaled inside clamping members 18, andappropriate gland joints could be provided at clamping members 18 topermit variation in pressure inside the rollers during operation of thevehicle. The inflation pressure of the rollers should be varied withdifferent operating conditions and with different materials from whichthe rollers may be formed, but in general the pressure inside therollers is preferably of the order of 1 to 10 p.s.i. To avoid excessivepressure from building up in the air rollers due to indentation causedby encountering obstacles, valve-controlled air exit means may beprovided in the rollers, together with means for reinflating the rollersduring operation from an air reservoir or air supply pump.

FIG. 4 shows a hollow flexible skirt-like member 20 communicating withthe elongated transverse duct 10 and depending downwardly from the basestructure of the vehicle so as to form the fluid curtain at a pointbelow the clearance space between the upper edge of the roller 5 and thelower surf-ace of the base structure. This arrangement employs someadvantages over the corresponding arrangement shown in FIG. 1 especiallyin cases where the clearance is substantial.

FIG. 5 shows in more detail how a roller 4 may be pivotally mounted tothe base structure of the vehicle. Thus arm 11 is pivoted about pivotpoint 19 so as to permit roller 4 to swing counterclockwise as viewed inFIG. 5 upon encountering a projecting obstacle. In order to per! mitroller 4 to pivot rearwardly to a greater extent upon encounteringlarger obstacles, but without unduly increasing the clearance spacebetween the roller and the base structure, a receiving well preferablyis formed in the lower surface of the base structure to partiallyreceive the roller when it is pivoted rearwardly to a substantialextent. Such a well is formed by wall 28 in the general manner shown inFIG. 5, this wall of the receiving well being constructed so as toconform generally with the path followed by the upper surface of theroller 4 as the roller is pivoted about the axis 19. This constructionmaintains the clearance space between the roller and the base structureat approximately the same dimensions as the roller moves about its pivotpoint.

The side wall members of the machine may be extensible and retractableto allow for adjustment :of their height to suit prevailing conditions.For example, for use over water the side walls may be in the lowposition, or even lower than the lower extremities of the air rollers.Because of their alignment with the fore and aft axis of the vehicle,their resistance to motion through water will be small, and it may beconvenient for the bottom edges of the side walls to be immersed, orpartly so, in order to minimize escape of cushion air. For progressionover ground, relatively short side walls are often desirable, and thusthe side walls may be retracted to a convenient height depending uponthe nature of the ground surface. An exemplary arrangement forretracting and extending the side wall members is shown in FIG. 6. Rackgears 21 and 22 may be provided'on 'the side wall member 3 to cooperatewith pinions 22 which are driven by an electric motor 24 through a gearbox 23. The gear box and the driving motor obviously would be fixed tothe base structure of the vehicle.

In order to minimize air cushion losses to a practical extent, aflexible or yieldable sealing arrangement should be provided to seal thespace between the roller supporting arms and the inner surfaces of theside wall members. An exemplary arrangement is shown in FIGS. 7 and 8where an elongated flexible member 25 is shown as being folded over andfixed at its respective longitudinal edges to the inner surface of aside wall member 3 and the outer surface of a roller supporting arm 11.By using such a flexible and folded member, the seal can be maintainedduring pivotal movement of the roller supporting arm, and member 25 willbe so proportioned as to permit pivotal movement of the rollersupporting arm to the design limit. Members 25 can be fixed to therespective surfaces in any convenient manner, but preferably the methodof attachment should be such as to permit re placement of members 25 ifthey should become damaged. A bolted clamp attachment is quite suitable.

For use in areas where the obstacles which reasonably can be expected tobe encountered are not such as to call for the use of large rollers ofthe type previously described, but which are such as possibly to createundue wear and tearing of flexible skirts of standard design, thearrangement shown in FIG. 9 can be substituted for or used inconjunction with the larger inflated rollers previously described. Thearrangement of FIG. 9 comprises an impervious flexible skirting memberdepending downwardly from the base structure of the vehicle and havingone or more rollers 27 carried at the lower edge thereof. Flexiblediaphragm-like retaining members 29 can be incorporated to extendbetween the base structure of the vehicle and the flexible skirtingmember 26 to provide support for the skirting member against outwardmovement due to the pressure of the pressurized supporting cushion. Thesmall roller 27 will function in much the same manner as the largerrollers previously described upon encountering relatively smallobstacles, whereas it will tend to minimize or reduce the possibility ofdamage to the skirting member 27 upon encountering larger obstacles.Because of the better seal which is accomplished by the skirting member26, the use of a fluid curtain in the manner previously described isgenerally unnecessary. However, by forming the flexible skirting member26 as two spaced flexible walls connected by vertically extendingflexible diaphragms, the flexible skirting member if desired can be usedas a flexible conduit so as to permit pressurized fluid to be conductedtherethrough for discharge as a fluid curtain in the vicinity of thesmall roller 27, the fluid curtain preferably being directed on theinward side of the small roller.

The manner of operation of a machine according to the invention will beapparent to those skilled in the art from the foregoing description andillustration of an exemplary embodiment. Upon contact with relativelysmall obstacles the inflated rollers will roll about their taxes andgive way slightly inwardly so as to minimize the retarding effectagainst forward movement which normally would be created by encounteringthe obstacle. Upon encountering larger obstacles the inflated rollerswill also function in this manner, but in the preferred embodiment theyalso will pivot about their points of attachment to the base structureof the machine so as to clear the larger obstacle without substantiallyretarding the forward movement of the machine and without anysubstantial loss of cushion pressure.

While the rollers will operate satisfactorily due to their freelyrotatable mountings, in some instances it may be desired to providedriving arrangements for the rollers. Such arrangements could take theform of belt and pulley drives or chain and sprocket drives, the belt orchain extending downwardly along the roller support arms 11 and 13.Also, it may be desired for some applications to make the rollersthemselves vertically adjustable, and this can conveniently beaccomplished by incorporating an adjustable hydraulic piston andcylinder arrangement in the roller supporting arms, with hydraulic fluidlines leading to a convenient point of control in the base structure ofthe vehicle. Where it is desired to control the pivot positions of therollers about their pivot axes, simple flexible tension members, such ascables, can extend between the lower ends of the roller support arms anda simple winding mechanism in the base structure of the vehicle so as topermit the rollers to be pivotally retracted against the force of theshock absorbers, or alternatively an overriding hydraulic piston andcylinder arrangement could be incorporated in the shock absorbersthemselves so as to permit varying of the effective length of the shockabsorbers. It may be found desirable to utilize such arrangements toraise or pivot the forward roller to allow ingress of air at rampressure to the pressurized gas cushion during periods of highoperational speed. For machines that are intended to be used primarilyover ground as opposed to water, flexible bottom extensions for the sidewall members will be advantageous.

It will be apparent to those skilled in the art that the particularembodiment or embodiments illustrated and described herein aresusceptible of various modifications without departing from the conceptand spirit of the invention. Therefore, it should be understood that theforegoing particular embodiment or embodiments are to be taken asexemplary of the invention, and that the invention is to be limited onlyby the subjoined claims as interpreted in the light of the foregoingspecification.

Having thus fully described my invention in the manner required by thestatute, I claim:

1. A ground effect machine comprising a platform-like base structure,two spaced side wall members depending downwardly from said basestructure on opposite sides of and extending in the direction of thelongitudinal center line of said base structure, at least one roller,means rotatably mounting said roller to extend between said side wallmembers on one side of the transverse center line of said base structurewhereby said roller and said side wall members define at least threeboundary sides of a pressurized gas supporting cushion under said basestructure, and means for supplying pressurized gas to the area undersaid base structure defined by said roller and said side wall members,said pressurized gas supplying means comprising a downwardly directednozzle opening extending transversely between said side wall members andadjacent to said roller but between said roller and the transversecenter line of said base structure, and blower means for supplyingpressurized gas to said nozzle opening so as to form a fluid curtain tominimize air loss between the upper surface of said roller and thebottom surface of said base structure.

2. A ground effect machine as recited in claim 1 further comprising asecond roller, and means rotatably mounting said second roller to extendbetween said side wall members on the opposite side of said transversecenter line from the first said roller, whereby said side wall membersand said two rollers define the four boundary sides of a pressurized gassupporting cushion under said base structure.

3. A ground effect machine as recited in claim 2 wherein said rollersare hollow and formed from a flexible material and are inflated at arelatively low pressure.

4. A ground effect machine as set forth in claim 1 wherein said meansrotatably mounting said roller comprises means pivotally mounted on saidbase structure for permitting pivotal movement of said roller uponencountering obstacles during translational movement of said basestructure, and means for urging said roller toward its original positionafter passage over an obstacle.

5. A ground effect machine as recited in claim 1 wherein said meansrotatably mounting said roller comprises 7 two arms pivotally mounted tosaid base structure and extending downwardly adjacent the respectiveinner surfaces of said side wall members to the axial ends of saidroller, and means for sealing the spaces defined between said arms andthe inner surfaces of said side Wall members.

6. A ground effect machine as recited in claim 1 wherein said side wallmembers are retractably mounted in said base structure, and means foradjusting said side wall members vertically relative to said basestructure.

7. A ground eflect machine as recited in claim 1 wherein said downwardlydirected nozzle is formed in the lower edge of a hollow flexible memberextending dwn wardly from said base structure to a point below the uppersurface of said roller.

References Cited by the Examiner UNITED STATES PATENTS 3,027,860 4/1962Priest -7 3,077,174 2/1963 Cockerell 1807 3,189,115 6/1965 Rethorst180-7 3,195,666 7/1965 Lewis et a1. 180--7 BENJAMIN HERSH, PrimaryExaminer. M. S. SALES, Assistant Examiner.

1. A GROUND EFFECT MACHINE COMPRISING A PLATFORM-LIKE BASE STRUCTURE,TWO SPACED SIDE WALL MEMBERS DEPENDING DOWNWARDLY FROM SAID BASESTRUCTURE ON OPPOSITE SIDES OF AND EXTENDING IN THE DIRECTION OF THELONGITUDINAL CENTER LINE OF SAID BASE STRUCTURE, AT LEAST ONE ROLLER,MEANS ROTATABLY MOUNTING SAID ROLLER TO EXTEND BETWEEN SAID SIDE WALLMEMBERS ON ONE SIDE OF THE TRANSVERSE CENTER LINE OF SAID BASE STRUCTUREWHEREBY SAID ROLLER AND SAID SIDE WALL MEMBERS DEFINE AT LEAST THREEBOUNDARY SIDES OF A PRESSURIZED GAS SUPPORTING CUSHION UNDER SAID BASESTRUCTURE, AND MEANS FOR SUPPLYING PRESSURIZED GAS TO THE AREA UNDERSAID BASE STRUCTURE DEFINED BY SAID ROLLER AND SAID SIDE WALL MEMBERS,SAID PRESSURIZED GAS SUPPLYING MEANS COMPRISING A DOWNWARDLY DIRECTEDNOZZLE OPENING EXTENDING TRANSVERSELY BETWEEN SAID BETWEEN WALL MEMBERSAND ADJACENT TO SAID ROLLER BUT BETWEEN SAID ROLLER AND THE TRANSVERSECENTER LINE OF SAID BASE STRUCTURE, AND BLOWER MEANS FOR SUPPLYINGPRESSURIZED GAS TO SAID NOZZLE OPENING SO AS TO FORM A FLUID CURTAIN TOMINIMIZE AIR LOSS BETWEEN THE UPPER SURFACE OF SAID ROLLER AND THEBOTTOM SURFACE OF SAID BASE STRUCTURE.